aes-encrypt.py

import string
from random import choice

from Crypto import Random
from Crypto.Cipher import AES


KEY = ''.join([choice(string.printable) for i in range(16)])


def padding(text, bs):
    return ''.join([text, (bs - len(text) % bs) * chr(bs - len(text) % bs)])


def unpadding(text):
    return text[:-ord(text[-1])]


def encrypt(text):
    iv = Random.new().read(AES.block_size)
    aes = AES.new(KEY, AES.MODE_CBC, iv)
    return ''.join([iv, aes.encrypt(padding(text, AES.block_size))])


def decrypt(cipher):
    iv, ci = cipher[:16], cipher[16:]
    aes = AES.new(KEY, AES.MODE_CBC, iv)
    return unpadding(aes.decrypt(ci))


if __name__ == '__main__':
    while True:
        msg = raw_input('Msg: ')
        bytes_msg = str.encode(msg)
        print len(bytes_msg)
        cipher = encrypt(bytes_msg)
        print 'Encrypt:',  cipher
        print 'Decrypt:', decrypt(cipher)